There is a heretofore known connector comprising a connector main body with a hook at one end, the connector main body including a housing hole formed so as to open toward the front end of the hook; a guide slot formed along the housing hole for communication between the housing hole and the exterior thereof; an opening-closing rod retained in the housing hole in movable relation toward and away from the front end of the hook, for openably closing the mouth of the hook; a spring placed in the housing hole for urging the opening-closing rod in a direction to close the mouth, or closing direction; and an outwardly protruding opening-operation body attached to the opening-closing rod through a coupling portion which slides in the guide slot. See, for example, Japanese Unexamined Patent Publication JP-A 62-288711 (1987).
As shown in FIG. 6, for example, a conventional connector of such a type is fitted, at its hook, to a ring or other attached to an accessory such as a collar or a harness worn by a pet such as a dog for connection with a leash, a tether, or the like. During use, however, as a pet such as a dog moves around, the opening-operation body may be accidentally pressed, thereby moving the opening-closing rod in a direction to open the mouth, or opening direction. In this case, the mouth of the hook is opened with the consequent accidental detachment of the connector from e.g. the ring.
In this regard, there is another conventional connector designed with the aim of preventing the connector from accidentally becoming detached from the retaining ring. That is, a locking groove is formed in the connector main body by branching the guide slot, and the coupling portion of the opening-operation body is made engageable in the locking groove. Upon the engagement of the coupling portion in the locking groove, the opening-closing rod is locked in a closing position to close the mouth of the hook, whereby the mouth of the hook is restrained from being opened. See, for example, Japanese Unexamined Patent Publication JP-A 2009-72080.